A 57-year-old man with recurrent depression, resistant to drug therapy, was scheduled for a course of eight electroconvulsive therapy treatments. The patient had undergone seven treatments without incident over the previous 3 weeks. Immediately following the final treatment, the patient suffered cardiovascular collapse, culminating in cardiac arrest with electromechanical dissociation. Despite resuscitative measures, the patient died. Post-mortem examination found the cause of death to be cardiac tamponade, secondary to cardiac rupture.